x86/mce/AMD: Document some functionality

In an attempt to aid in understanding of what the threshold_block
structure holds, provide comments to describe the members here. Also,
trim comments around threshold_restart_bank() and update copyright info.

No functional change is introduced.

Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
[ Shorten comments. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1457021458-2522-6-git-send-email-Aravind.Gopalakrishnan@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/amd_nb.h

@@ -27,15 +27,23 @@ struct amd_l3_cache {
 };
 
 struct threshold_block {
-	unsigned int		block;
-	unsigned int		bank;
-	unsigned int		cpu;
-	u32			address;
-	u16			interrupt_enable;
-	bool			interrupt_capable;
-	u16			threshold_limit;
-	struct kobject		kobj;
-	struct list_head	miscj;
+	unsigned int	 block;			/* Number within bank */
+	unsigned int	 bank;			/* MCA bank the block belongs to */
+	unsigned int	 cpu;			/* CPU which controls MCA bank */
+	u32		 address;		/* MSR address for the block */
+	u16		 interrupt_enable;	/* Enable/Disable APIC interrupt */
+	bool		 interrupt_capable;	/* Bank can generate an interrupt. */
+
+	u16		 threshold_limit;	/*
+						 * Value upon which threshold
+						 * interrupt is generated.
+						 */
+
+	struct kobject	 kobj;			/* sysfs object */
+	struct list_head miscj;			/*
+						 * List of threshold blocks
+						 * within a bank.
+						 */
 };
 
 struct threshold_bank {

arch/x86/kernel/cpu/mcheck/mce_amd.c

@@ -1,5 +1,5 @@
 /*
- *  (c) 2005-2015 Advanced Micro Devices, Inc.
+ *  (c) 2005-2016 Advanced Micro Devices, Inc.
  *  Your use of this code is subject to the terms and conditions of the
  *  GNU general public license version 2. See "COPYING" or
  *  http://www.gnu.org/licenses/gpl.html
@@ -201,10 +201,7 @@ static int lvt_off_valid(struct threshold_block *b, int apic, u32 lo, u32 hi)
 	return 1;
 };
 
-/*
- * Called via smp_call_function_single(), must be called with correct
- * cpu affinity.
- */
+/* Reprogram MCx_MISC MSR behind this threshold bank. */
 static void threshold_restart_bank(void *_tr)
 {
 	struct thresh_restart *tr = _tr;